Recent development of synthetic preparation methods for guanidines via transition metal catalysis

Abstract

Multisubstituted guanidines have received much attention because of important applications in many fields, such as pharmaceutics, organometallic and coordination chemistry, and organic synthesis. Although classical methods are available for the preparation of guanidines, synthetic preparation approaches to guanidines are still in great demand. In this review, we summarize recent developments on synthetic methods via the C-N bond formation. Three aspects are included: transition-metal-catalyzed guanidine synthesis based on classical methods; catalytic guanylation reaction of amines with carbodiimides; and tandem catalytic guanylation/cyclization reactions.

Guanidine Metal Complexes for Bioinorganic Chemistry and Polymerisation Catalysis

“…The copper complexes were tested in the catalysed oxidation of 3,5-ditert-butylcatechol. With nickel (II) 6 (Fig. 33a) were obtained.…”

“…The copper-superoxo 1:1 CuO 2 species is formed reversibly from the corresponding [Cu(TMG 3 tren)] analogue at low temperatures (Scheme 4), it was spectroscopically and theoretically characterised in 2004 [48,51], and the structure of the end-on superoxo [Cu II 6 ] complex was determined in 2006 ( Fig. 12) [49,52].…”

“…The guanidine ligand incorporated strong donating N donor atoms which stabilised Cu I metal centres and exhibited trigonal coordination. The respective copper complexes with non-coordinating anions were used in oxygen activation (SbF 6 À , PF 6 À ) (see Sect. 2.2), whereas the CuCl derivative (Fig.…”

“…A special class of guanidinates are the imidazolin-2-iminato ligands which have been established as powerful ancillary ligands in catalysis [5]. Guanidines have found widespread use in coordination and organic chemistry, as pharmaceuticals, sweeteners, catalysts, etc., and a multitude of synthetic approaches has been reported [6,7].…”

Catalyst free C–N bond formation by the reaction of amines with diimides: bulky guanidines

“…5,6 The guanidine moiety is an essential substructure in many biologically and pharmaceutically important molecules and also natural products. 13,14 More importantly, Zhang and coworkers have shown four types of mechanisms for the catalytic guanylation of amines with carbodiimides. 8 In 2006, Coles in his excellent review pointed out that the guanidine framework constitutes a versatile ligand set for use in coordination chemistry.…”